Monday, May 7, 2012

As any beer drinker knows, the ingredients to the world’s greatest beverage are water, yeast, hops, and a starch source, typically malted barley. These basic ingredients have been used for hundreds of years. However, beer producers are not required to list their ingredients, so the typical consumer has no way of knowing whether brewers are using barley or some other sort of starch source, such as corn. Corn ferments faster and is far cheaper than barley, so one could see the desire for lesser-quality brewers to use it in place of barley.

Being a beer purist myself, I used SCIENCE to see which beers contained corn. Corn is a C 4 fixating plant, while barley is C3. This means is that they have different carbon-13 isotopic signatures. I theorized that there would be negative trend between corn content and price. I also theorized that there would be geographic trends of C4 content, such as a lack of corn in German beers and a higher amount of it in American and possibly Mexican beers.

Unfortunately the mass spectrometer broke the first time around and I lost most of the poorer-quality beers (apparently machines find Natty just as disgusting as the rest of us). Having already drank the remainder of my samples and an extremely limited time before the due date of the project, I was stuck with the samples that you see in the graph and unable to confirm or deny either of my hypotheses, although the results are still interesting.

Plants that process carbon by the C4 pathway (such as corn) have a δ13C of about -10‰ to -16‰. C3 plants (barley) have a δ13C of -24‰ to -33‰. Most beers that were sampled were primarily C3 (probably barley, but rice is also a possibility), although several (Dos Equis and Modelo) appear to be partially made of a C4 plant, likely corn. The nitrogen variation (vertical axis) is probably due to differences in fertilizer. What sticks out most is how much Beck’s Non-Alcoholic differs from ordinary Beck’s. And PBR is odd, but I think we all knew that already.